X-ray volume imaging in image-guided radiotherapy

Treatment simulation has significantly improved the accuracy and precision of radiation therapy delivery. A new generation of therapy systems promises to take the simulation and imaging process to a new level of accuracy; however, this will require changes in the workflow process. We describe the first generation of these devices, review the various imaging options and how they might be used in the clinic to improve treatment outcomes, and suggest several workflow approaches. Workflows discussed include on-line interventional, off-line adaptive, and off-line predictive approaches, with both geometric and dosimetric considerations. These changes will place new knowledge requirements on the medical dosimetrist and will necessitate involvement in the development of new departmental processes.